ASoC: wm8978: pll incorrectly configured when codec is master

When MCLK is supplied externally and BCLK and LRC are configured as outputs
(codec is master), the PLL values are only calculated correctly on the first
transmission.  On subsequent transmissions, at differenct sample rates, the
wrong PLL values are used.  Test for f_opclk instead of f_pllout to determine
if the PLL values are needed.
Signed-off-by: Eric Millbrandt <emillbrandt@dekaresearch.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org

sound/soc/codecs/wm8978.c

@@ -782,7 +782,7 @@ static int wm8978_hw_params(struct snd_pcm_substream *substream,
 		wm8978->mclk_idx = -1;
 		f_sel = wm8978->f_mclk;
 	} else {
-		if (!wm8978->f_pllout) {
+		if (!wm8978->f_opclk) {
 			/* We only enter here, if OPCLK is not used */
 			int ret = wm8978_configure_pll(codec);
 			if (ret < 0)